CANNABIS: HUMIDITY MANAGEMENT Controlling humidity for indoor cannabis growth can be a delicate balancing act

If you talk to any experienced PRESERVING PROPAGATING TISSUE VEGETATIVE DEVELOPING DRYING & cannabis grower, they will tell you the GENETICS PLANTS CULTURE GROWTH BLOOMS CURING management of humidity is one of the Mother Clones Tissue in Young Flowering Dry most important factors in producing Plants Solution Plants Plants Plants a quality crop. A well-monitored dehumidification strategy can result in a winning payload of healthy buds and minimize unnecessary problems (like powdery mildew) that can lead to crop loss and time wasted. IMPORTANCE OF HUMIDITY CONTROL Humidity, to a certain extent, determines how much water your plants will consume. The dryer the air, the more they will consume. When they are young, cannabis plants prefer higher humidity levels that tend to promote faster growth. Their RH = Relative Humidity leaves will pull water directly from the air to grow foliage while the plant develops its root system. As the plant Growers typically develop strategies to manage humidity matures, however, a lower humidity level should be established to prevent levels for each stage of plant growth formation of mildew or mold. PROPAGATING PLANTS VEGETATIVE FLOWERING DRYING BUDS Relative humidity (RH) is a measure The clone is the most Once the young cannabis Once flowering is triggered High ventilation, low of the amount of moisture in the air vulnerable stage of plants have properly by shortening the light humidity, and slightly compared to what the air can sustain at the cannabis plant’s rooted, the humidity can be cycle and reducing lower temperature are a given temperature. Cannabis growers development, requiring lowered, and temperatures temperature, flowers required during the drying typically develop strategies to manage high humidity and slightly increased to boost start to develop resins stage to reduce the water consistent temperatures metabolic activity in both containing THC and CBD. content of cannabis buds, relative humidity at each stage of to prevent excessive drying the plants and the soil. During this stage, humidity remove unwanted pigment growth (see graph on right). of young roots during In addition, high light should be kept low to and chlorophyll, and Temperature and relative humidity are propagation. Young clones intensities and longer prevent mold, mildew prevent mold formation. are entirely reliant on high daylight cycles are applied and other diseases from closely interrelated. If the temperature humidity to get water to establish desired plant forming on the buds. is too hot and dry there is potential for through their leaves from mass and root base prior the air to extract moisture out of the the air. to blooming. plant resulting in slower growth. Cool and humid conditions, is easily designed into the overall refrigeration system by the on the other hand, can cause mold or fungus as well as slow manufacturer of a controlled growing environment, but it is growth. Controlling both temperature and RH at the same not an option that can be retrofitted into an installed system. time is imperative to achieving optimum growing results. For existing grow rooms, externally mounted systems are more appropriate. AIR MOVEMENT Dry Air to Inside of Room Continuous air movement over and around your plants prevents stratification and CO2 depletion, reduces odor, and increases transpiration and stomata function. In terms of humidity, circulating air keeps the cannabis leaves dry enabling the plant to pull in more nutrients and to absorb more water Damper at the roots. Effective air circulation also helps in preventing humid microclimates and wet spots from forming on the plants, Fan Cooling reducing the chance of mold, bud rot or white powdery mildew. Coil DEHUMIDIFICATION STRATEGIES For cannabis production, growing environments are typically dehumidified by the air conditioning system. Separate coil dehumidification MECHANICAL / REFRIGERATION A separate coil dehumidifier is mounted externally in the growth A given volume of air can hold progressively less water vapor as room or chamber. It draws air from the growth area through a its temperature decreases. By manipulating the temperature of cooled coil to remove the moisture by condensation, and returns the air, it is possible to reduce the humidity relative to the dew the dryer air to the growth area. This method of mechanical point. This can be achieved with the refrigeration system using dehumidification is especially attractive for retrofits or spaces bypass dampers or separate coils. being converted for cannabis production.

Bypass damper dehumidification In a typical refrigeration system for a controlled growth environment, water vapor is removed from the circulating air by temporarily chilling it to below the dew point, thus condensing some of the water vapor. To do this, a bypass Cooling Coil Fan damper is used to re-route the air around the main cooling Roof coil allowing the coil to be run at a much cooler temperature, Wet Air Dry Air which causes the moisture in the air that is passing through From Room Back to Room the coil to condense and drain off. Bypass dehumidification

Advanced Environmental Control Systems: Cannabis Grow Rooms & Technologies: Management System Certified to ISO 9001

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